The invention concerns a novel family of chemical compounds derived from fatty compounds, characterised by the presence of two branches on the linear chain. These compounds are obtained by addition of ethylene to polyunsaturated compounds. The invention also concerns a process for the production of these compounds using anionic rhodium complexes in the presence of ethylene and certain fatty compounds.
The invention still further concerns the production of saturated derivatives of these double-branched compounds by partial or total hydrogenation of the primary compounds.
It has been known for more than 30 years that ethylene can be reacted with different dienes (U.S. Pat. No. 3,502,738). 1,4-hexadiene is obtained from butadiene, 3-methylhexadiene is obtained from isoprene and 2-vinylpentene is obtained from piperylene, each in the presence of various rhodium complexes. Ethylene has also been reacted with dienes whose two double bonds are within the body of the chain, one or both extremities being substituted by alkoxy or halogen groups (U.S. Pat. No. 3,742,080).
Ethylene or propylene is also known to react with fatty dienes, either of the vinyl-octadecenoate type when adding an ethylene group, which may or may not be conjugated, to produce single-branched compounds, or of the isobutyl-octadecenoate type if two ethylene groups are added, or of the isohexenyl-octadecenoate type if three ethylene groups are added to the fatty compound; the fatty compound usually used is a conjugated linoleic ester.
Addition of ethylene to produce single-branched derivatives is described in international patent application WO-91/11428 A1 and single-branched hydrogenated compounds are described in international patent application WO-91/11426 A1.
Ethylene derivatives were also obtained more than twenty years ago by D. G. Chasin et al using a Wittig reaction en the ketone in position 10. Hydrogenation of the ethylenated compound obtained enabled the author to make the corresponding alkyl 10-ethyl stearate (Chem Phys Lipids 6 8-30 (1971)).
Dimethyl stearate type compounds produced by skeletal isomerisation are also known but many other isomers are produced at the same time.
None of the prior art describes fatty derivatives having two branches each comprising two carbon atoms.